Dietary intervention study conducted with fibre rich functional and sustainable smoothie made using leftover apple pomace from apple cider industry

Sustainability and environmentally friendly production are the key elements in The Farm to Fork Strategy that aims to reduce the environmental and climate impact. An important task is to reduce the leftovers to the minimum in every step of food production. Every year there is more than 5 million tons of apple pomace leftover from apple juice industry. Most of that goes to landfill, although it is nutritious material, e.g., containing different carbohydrates and dietary fibres. Our aim was to maximize the separation of edible part of apple pomace and use obtained apple puree to create smoothies with enriched fibre content. We tested different fibres and fibre mixes in in vitro study to find best possible recipe for the smoothie that would support the diversity of gut microbiome. Development and testing phase ended with successful prototype that contained 1/3 of apple puree obtained from apple pomace and complex dietary fibre mix. We also created low-fibre smoothie as placebo product for our dietary intervention study. Dietary intervention study lasted 11 weeks, 39 participants. Our results from dietary intervention study showed that consumption of high fibre smoothie influenced the human gut microbiome, blood lipid characteristics and general well-being of participants. We saw reduction of bacteria associated with overweight or inflammation (e.g., Coprococcus comes, Dorea, Ruminococcus torques), and increase of active fermentative bacterium (Lachnospira). The results from blood lipid analysis showed decrease in low-density lipoprotein (LDL) and non- high-density lipoprotein (non-HDL) cholesterol. Overall, our dietary intervention study showed the beneficial effects of prototype smoothie consumption.